> Alan Cox <alan@lxorguk.ukuu.org.uk> writes:> > >> And if it's right, unfortunately, I guess we can't return -EAGAIN in> >> this case to preserve behavior.> >> > To avoid the EAGAIN the close needs to block until all queued I/O has> > been processed by the ldisc the other end. That's not standards> > guaranteed or even what happens with a non pty port, but it is doable> > unless you take signals - we can't block signals or it can all deadlock.> > Just a quick hack though. Is this wrong/unpreferable way?> > n_tty_read() checks the pending buffer and consume it before> input_available_p().

That won't change the fact that the process could have exited. You canfix the -ENXIO reporting that way (and it is basically what theEOFPENDING/EOF patch did), but the only way I can see to fix theassumption that the process exit means all the data is in the ldisc theother end ready to use is to actually to make the close() path block -but with some kind of limits to prevent deadlocks.

Given the assumptions in emacs are wrong, low_latency fixes the realworld cases and we are standards compliant perhaps we are trying toohard ?